An optical fiber ribbon includes a plurality of optical fibers arranged in a row and an outer coating formed around the optical fibers. Each of the optical fibers has a core, a cladding, and a non-strippable thin coating made of synthetic resin with a Young's modulus of 50 kg/mm2 to 250 kg/mm2 at room temperature and coated around the cladding. The concentricity of the core to the diameter of the non-strippable thin coating is 1 &mgr;m or less.